We know that aside from Kryptonite, red solar energy is also a weakness to Kryptonians, as it replaces the "more energetic" yellow solar energy in their cells, robbing them of their powers. We've seen this put to deadly effect before, like when humanity turned their own sun red:

Where is the camera?

But what about the effects of redshifting? That is for example, if Superman were to fly away from the sun at around 1/6th the speed of light, then the yellow light would be shifted into red, and theoretically rob him of his powers. Or, in the situation above, assuming he flew towards the sun at that speed, it would appear yellow again, theoretically charging him.

Have any stories touched on this property of light as a weakness, either unintentionally or as exploited by a villain? For the sake of it, I'll even accept if there's anything that shows Superman to be weaker at sunset, when refraction causes the relative proportion of red light to be significantly higher.

  • 1
    The use of redshifting is shown in the DC Universe in the graphic novel Ganthet's tale, written by Larry Niven, and drawn by John Byrne in which it is used to turn a Green Lantern's light into the yellow light against which the Guardian power has no defense, in a battle with a rogue Guardian and a Zamaron, and their offspring. The effect has not so far as I know been shown in use against Superman perhaps because generating red light directly is far simpler, whereas in the space combat in Ganthet's tale seeming to run away was a surprise tactic. Commented Mar 14, 2018 at 17:40
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    What about "red sky at night ....", does Superman's powers vary with the time of day or does he store the yellow energy of the Sun? In which case, wouldn't this be of interest to the question?
    – user66716
    Commented Mar 14, 2018 at 18:23
  • @SimonBucher-Jones That's particularly interesting... It confirms the effect is a part of the DCU's physics. Having not read it though, I'm curious how they managed to put that to use, since you have to be travelling away from whatever it is you're attacking/defending against in order to redshift from green to yellow. To draw closer to it, it wouldn't be yellow anymore.
    – Mwr247
    Commented Mar 14, 2018 at 19:57
  • As I tried t explain Green Lantern pretends to flee, but by withdrawing at a substantial proportion of light speed he 'yellow' shifts the green power he can project from his ring, and projects that back along his path into the battle. Commented Mar 15, 2018 at 23:11

2 Answers 2


The DCAU had an episode like this. The episode Solar Power had a villain use satellites to filter the yellow wavelengths out, leaving only red.

Superman appears to save Lois but finds himself unable to handle the trolley's weight. As he struggles to hold it up, Lytener appears floating beside him in a specialized suit, now calling himself Luminus. He says that things will only get worse. Superman barely manages to save Lois, after which he tests his powers, and finds that they are still fading. The clouds part and much to Superman's surprise, the sky is red.

Scientists explain that Lytener has hijacked an array of LexCorp satellites and used them to project a force field over the Earth; the sun is still yellow, but only the red rays are getting through the field, effectively making a red sun like that of Krypton. Lois calls up Luthor and accuses him of being an accomplice to Lytener's plan but he calmly denies it.

  • I was going to say this didn't match the question, but with the "sunset" clause it does seem like it should count, technically at least.
    – RDFozz
    Commented Mar 14, 2018 at 18:15
  • This definitely fits the "manipulation of normal solar energy into red solar energy" idea. Good find =) Still want to see if there's anything out there specifically on redshifting before accepting anything though.
    – Mwr247
    Commented Mar 14, 2018 at 19:50

While in some stories in the past, red sun energy has "sapped away" Superman's powers, the currently/commonly accepted effect is different.

Red sun energy is too weak to allow a Kryptonian to recharge their power. So under a red sun, a Kryptonian would slowly lose their powers as their repository of solar energy is used up. The same thing would happen if they remained in the dark, away from our (or any sufficiently powerful) sun's rays.

In the shot above, one would have to assume that the energy expended to survive in space is quite great, and the Kryptonians, who had only been absorbing Yellow energy for a brief period of time, did not have enough of an internal storage to last long.

The "red sun chamber" from Superman II, OTOH, worked by forcing the yellow energy from a Kryptonian's cells, and rendering them unable to process and absorb more yellow energy.

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